The subject of this invention is a prosthesis for the surgical treatment of hernias.
A hernia is a defect in the abdominal wall into which the peritoneum and the intra-abdominal viscera thrust themselves. It is most often located at the groin and the navel. There are also hernias called ruptures located at incisions made during a surgical operation on the abdomen.
Surgical repair of hernias has two goals, first, to assure the solidity of the wall definitively so there will be no recurrence and, second, to do it with as little inconvenience as possible, particularly with little pain in order to permit rapid resumption of activity.
We note that where inguinal hernia in men is concerned, the repair work is more complicated than the simple closing of an orifice because the inguinal cord which contains the testicle ducts and the vas deferens must be preserved.
The surgical treatment of hernias may be carried out by sutures pulling together the edges of the hernial orifice or by putting in place a prosthesis in synthetic mesh to seal the orifice without bringing together the edges. With a prosthesis, the absence of tension alleviates the pain and reduces the risk of recurrence.
There are several types of prostheses, all made of a supple mesh of synthetic material, notably of material like dacron, polyethylene, PTFE, etc.
Existing prostheses are offered in several shapes. The most common have the shape of a rectangle or a square of supple tissue that can be applied as is or cut as desired.
Some are precut, usually in oval shape adapted to the area of weakness of the inguinal hernia with a slit for passage of the inguinal cord. Others are molded with a certain convexity adapted to the shape of the abdominal wall.
There is, also, a prosthesis called xe2x80x9cplugxe2x80x9d which consists of a sort of conically shaped cork, intended to be introduced into the hernial orifice to obstruct it.
The setting in place of prostheses may be done in various ways, in particular by the inguinal, retroperitoneal route or by laparoscopy.
The retroperitoneal method or Stoppa procedure necessitates making a large median abdominal incision in order to access the retroperitoneal space and the bottom surface of the muscular system. Admittedly this technique permits the expansive spreading out of a supple prosthesis on the bottom surface of the muscular wall, so that abdominal pressure holds the prosthesis against the wall around the hernial orifice, giving it great solidity.
However, you will see that the retroperitoneal method has the disadvantages of requiring a debilitating and painful incision and, moreover, cannot be done under local anesthetic.
Laparascopy permits placing the prosthesis in the retroperitorieal space, while avoiding the making of a large incision. However, this technique is proving difficult to perform and requires great expertise on the part of the surgeon, not to mention that it cannot be done under local anesthetic. In addition, this technique is likely to expose the patient to complications, some of which may be serious.
The inguinal route consists of cutting directly into the inguinal region and then, after dissection of the anatomic elements, putting the prosthesis in place, either in the retroperitoneal space (Rives procedure), or on the surface wall of the musculo-aponeurotic system (Lichtenstein procedure).
This technique has the advantage of being simple, easily reproduced and doable under local anesthesia. However, we see that with this technique it is particularly difficult to set a prosthesis in place in the retroperitoneal space, guaranteeing optimal solidity. In fact, due to the narrowness of the passage, spreading out prostheses which are at present supple, proves difficult and they have a tendency to wrinkle. The absence of perfect spreading on the bottom surface of the muscular wall brings a risk of engagement of the peritoneal sac and increases the possibilities of a relapse.
To make up for these disadvantages, various devices facilitating the setting in place and spreading out of prostheses in the retroperitoneal space have been proposed. So, through documents EP-0.557.964 and WO-92.06639, we know of apparatus consisting of a device that is intended to make deployment of the prosthesis in the retroperitoneal space easier. In fact, these pieces of apparatus consist of a tubular device completed by a sheath and a button permitting introduction of the prosthesis through a laparoscopy trocar and obtaining its deployment through that trocar.
We note that these devices are, in fact, mainly intended for putting in place prostheses by the laparoscopic method, but are not in any way intended to be used for the inguinal method in traditional surgery.
We also know from document WO-96.09795 of a prosthesis constituted by two superimposed layers of mesh surrounded by a peripheral frame intended to give it sufficient rigidity to facilitate setting it in place and spreading it out in the retroperitoneal space.
You will notice that this prosthesis is made up of several thicknesses of mesh in a non-resorbent material of a synthetic type and that the multiplication of these thicknesses leads to an increase of risks of intolerance by the organism, notably in case of infection.
The framework, also, is made up of a non-resorbent material and is presented in the form of a relatively thick and rigid ring with no interruption. This ring then rests against the femoral veins which, over time, may traumatize them and bring about complications. Moreover, the circumference of this prosthesis has rough patches due to cutting the free edge and intended to facilitate anchoring said prosthesis in the tissues of patients. These rough patches are also likely to traumatize the tissues, particularly the femoral veins and the vas deferens. In addition, this flat, rigid prosthesis does not fit properly the convex shape of the visceral sac and abdominal wall.
Finally, through document WO-97.23310, we know about a prosthesis composed of a supple sheet associated with a self-opening structural device intended to facilitate the deployment of the prosthesis in the retroperitoneal space when it is set in place through the inguinal orifice or by a laparoscopy trocar. This device can take on a curved shape, facilitating, solely, the expansion and setting in place of one of the ends of the prosthesis, but not resolving in any way the difficulties in spreading out the other end. This device can, also, take the shape of a ring whose circumference necessarily rests on the femoral veins with the risks of traumatism to them mentioned above. Moreover, the non-resorbent nature of the material used for the creation of the ring of this prosthesis once again exposes the patient to the risk of intolerance. Finally, the flat shape of this prosthesis is incapable of adapting properly to the convexity of the peritoneal sac and the viscera it contains.
The aim of this invention is to offer a prosthesis for the surgical treatment of hernias, implant able by the inguinal route under local or loco-regional anesthesia and that remedies the previously mentioned disadvantages.
The prosthesis that is the subject of this invention is characterized essentially by the fact that it is composed of two parts, that is, a synthetic non-resorbent mesh and a ring fixed to the peripheral edge of said synthetic mesh, said ring being made of a flexible resorbent material, permitting it to bend out of shape and then resume its initial form; and by the fact that said ring offers an interruption intended to be positioned over the femoral veins.
According to an additional characteristic of the device of the invention, the association of the said mesh and the said ring is realized in such a way that said mesh inside the said ring maintains a certain laxity, permitting it to take on a convex shape. This permits a perfect fit of the mesh to the convexity of the peritoneal sac and to the concavity of the bottom abdominal wall.
According to another additional characteristic of the prosthesis of the invention, at least one divider positioned diametrically is fastened by its ends to the ring and said divider, made of the same material as the said ring, is curved in shape and holds the mesh in a convex form.
According to another additional characteristic of the prosthesis of the invention, each of the end parts of the ring, on both sides of the interruption, presents, near the extreme edge, a zone of lesser resistance, permitting the said interruption to expand. This permits easy cutting of the ring.
According to another additional characteristic of the prosthesis of the invention, the mesh has, at each of the edge ends of the ring, a radial slit, creating a tongue intended to be applied over the femoral veins. This avoids, at the free edge of the prosthesis, any pressure whatsoever being applied on the said femoral veins.
According to a particular method of creation of the prosthesis of the invention, the latter is round in shape and comprised concentrically in the peripheral ring of an empty ring inside the mesh, linked to the said peripheral ring by means of spokes and presenting an interruption with regard to the interruption of said peripheral ring, the edge ends of the rings being linked in pairs by two of said spokes between which there is no mesh, while a cord is threaded peripherally close to the said peripheral ring; said cord permits, by traction on both of its ends, shaping the prosthesis into a frustum, presenting a space laterally.
According to an additional characteristic of the prosthesis of the invention, the ring or rings, together with the possible dividers or spokes, are made up of fine strips of round or flattened sections.
According to an additional characteristic of the prosthesis of the invention, the ring or rings, together with the possible dividers or spokes, are made of a resorbent material, notably like polyglycolic acid.